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use Winmerge inside of Git to file diff
...l added value comes from the ability to use that same diff tool to present all differences in one batch instead of presenting them sequentially, forcing you to close the diff tool windows one file at a time.
Update June 2012 (2-and-a-half years later):
Comparing directories instead of file-by-file...
How do you create a random string that's suitable for a session ID in PostgreSQL?
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random() gets called length times (like in many of the other solutions). Is there a more efficient way to choose from 62 characters each time? How does this perform compared to md5()?
– ma11hew28
Feb 1...
Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL?
...an work around it from within psql by executing the DDL statement conditionally:
SELECT 'CREATE DATABASE mydb'
WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'mydb')\gexec
The manual:
\gexec
Sends the current query buffer to the server, then treats each column of each row of the query's...
Formatting Decimal places in R
... However, in many domains (e.g., APA style, business reports) formatting requirements dictate that a certain number of decimal places are displayed. This is often done for consistency and standardisation purposes rather than being concerned with significant figures.
Solution:
The following code sh...
Why would adding a method add an ambiguous call, if it wouldn't be involved in the ambiguity
...comparisons of the three remaining candidates. There are three such pairs. All of them have identical parameter lists once we strip off the omitted optional parameters, which means that we have to go to the advanced tiebreaking round described in section 7.5.3.2 of the specification.
Which is bette...
R script line numbers at error?
...ou the line number, but it will tell you where the failure happens in the call stack which is very helpful:
traceback()
[Edit:] When running a script from the command line you will have to skip one or two calls, see traceback() for interactive and non-interactive R sessions
I'm not aware of anot...
General suggestions for debugging in R
...orite debugging routine:
When an error occurs, the first thing that I usually do is look at the stack trace by calling traceback(): that shows you where the error occurred, which is especially useful if you have several nested functions.
Next I will set options(error=recover); this immediately sw...
Why can't I forward-declare a class in a namespace using double colons?
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All other answers were confusing to me but this "you can't declare a class within a namespace from outside that namespace. You have to be in the namespace." was very helpful hint to remember.
– dashesy
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内存调试技巧：C 语言最大难点揭秘 - C/C++ - 清泛网 - 专注C/C++及内核技术
...他许多通用语言（如 Java™、Ruby、Haskell、C#、Perl、Smalltalk 等），每种语言都有众多的爱好者和各自的优点。但是，从计算角度来看，每种编程语言优于 C 或 C++ 的主要优点都与便于内存管理密切相关。与内存相关的编程是如...
Getting LaTeX into R Plots
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Here's an example using ggplot2:
q <- qplot(cty, hwy, data = mpg, colour = displ)
q + xlab(expression(beta +frac(miles, gallon)))
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